Final answer:
The term for a person lying on either side is the 'lateral' position, differing from the 'prone' (face-down) and 'supine' (face-up) positions.
Step-by-step explanation:
When a resident is lying on either side, he is in the lateral position. This is not to be confused with the prone or supine positions. Prone describes a face-down orientation, while supine describes a face-up orientation. The lateral position is used in various medical contexts, such as during physical examinations, surgical procedures, and when ensuring a patient's comfort and safety in a healthcare setting.